Previously, an in-tank fuel supply device, which is placed in the inside of the fuel tank, is widely used at the internal combustion engine of a vehicle. In a device, which is disclosed in the patent literature 1 as this kind of fuel supply device, a coupling stay couples between a cover body, which is installed to an upper wall of the fuel tank, and a pump unit, which is placed on a bottom wall of the fuel tank and is configured to discharge the fuel from the inside of the fuel tank toward the internal combustion engine.
The coupling stay of the device of the patent literature 1 includes a first slide member, which extends on a lower side of the cover body, and a second slide member, which is installed to the pump unit and is slidably fitted in a top-top-to-bottom direction relative to the first slide member.
However, in the device of the patent literature 1, the fuel tank expands and contracts in response to repeating of operation and stop of the internal combustion engine, so that the cover body and the pump unit follow the expansion and contraction of the upper wall and the bottom wall of the fuel tank. Therefore, when the expansion and contraction of the fuel tank become excessive, an excessive load is exerted along the coupling stay to the cover body, and thereby breakage of the cover body may possibly occur. In a case where the cover body is broken, fuel vapor may leak from the fuel tank. Therefore, the breakage of the cover body is not desirable.